The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Compressors are used in a wide variety of industrial and residential applications to circulate refrigerant within a refrigeration, heat pump, HVAC, or chiller system (generically referred to as “refrigeration systems”) to provide a desired heating and/or cooling effect. In any of the foregoing applications, the compressor should provide consistent and efficient operation to ensure that the particular refrigeration system functions properly.
Refrigeration systems and associated compressors may include a protection system that intermittently restricts power to the compressor to prevent operation of the compressor and associated components of the refrigeration system (i.e., evaporator, condenser, etc.) when conditions are unfavorable. The types of faults that may cause protection concerns include electrical, mechanical, and system faults. Electrical faults typically have a direct effect on an electrical motor associated with the compressor, while mechanical faults generally include faulty bearings or broken parts. Mechanical faults often raise a temperature of working components within the compressor, and thus, may cause malfunction of, and possible damage to, the compressor.
In addition to electrical faults and mechanical faults associated with the compressor, the compressor and refrigeration system components may also be affected by system faults attributed to system conditions such as an adverse level of fluid disposed within the system or to a blocked-flow condition external to the compressor. Such system conditions may raise an internal compressor temperature or pressure to high levels, thereby damaging the compressor and causing system inefficiencies and/or failures. To prevent system and compressor damage or failure, the compressor may be shut down by the protection system when any of the aforementioned conditions are present.
Conventional protection systems typically sense temperature and/or pressure parameters as discrete switches and interrupt power supplied to the electrical motor of the compressor should a predetermined temperature or pressure threshold be exceeded. Typically, a plurality of sensors are required to measure and monitor the various system and compressor operating parameters. With each parameter measured, at least one sensor is typically required, and therefore results in a complex protection system in which many sensors are employed.
Sensors associated with conventional protection systems are required to quickly and accurately detect particular faults experienced by the compressor and/or system. Without such plurality of sensors, conventional systems would merely shut down the compressor when a predetermined threshold mode and/or current is experienced. Repeatedly shutting down the compressor whenever a fault condition is experienced results in frequent service calls and repairs to the compressor to properly diagnose and remedy the fault. In this manner, while conventional protection devices adequately protect a compressor and system to which the compressor may be tied, conventional protection systems fail to precisely indicate a particular fault and often require a plurality of sensors to diagnose the compressor and/or system.